The American Association of University Professors (AAUP) conducts salary studies of college professors and publishes its findings in AAUP Annual Report on the Economic Status of the Profession. Pairs were formed by matching faculty in private and public institutions by rank and specialty. A random sample of 30 pairs yielded the data, in thousands of dollars, presented on the WeissStats site. Use the technology of your choice to do the following.

a. Apply the paired Wilcoxon signed-rank test to decide, at the 5% significance level, whether the data provide sufficient evidence to conclude that mean salaries differ for faculty in private and public institutions.

b. Compare your result in part (a) to the one obtained in Exercise 10.170 on page 497, where the paired t-test was used.

c. Which test do you think is preferable: the paired t-test or the paired Wilcoxon signed-rank test? Explain your answer.